feat(admin-room): Delete create-user command message

- Add the `event_id` of the user message to `AdminRoomEvent::ProcessMessage`
variant to work with it in `process_admin_message`
- Delete the user `create-user` command message if it's contain a plain password
because the admin room are unencrypted so the password
will be saved in the database if we didn't deleted it
- Create new function that delete the messages from admin room
called `delete_user_message`

Reported-by: Matthias Ahouansou <matthias@ahouansou.cz>
Helped-by: Matthias Ahouansou <matthias@ahouansou.cz>
Related-to: https://gitlab.com/famedly/conduit/-/issues/432
Signed-off-by: Awiteb <a@4rs.nl>

src/service/admin/mod.rs

@@ -20,6 +20,7 @@ use ruma::{
             message::RoomMessageEventContent,
             name::RoomNameEventContent,
             power_levels::RoomPowerLevelsEventContent,
+            redaction::RoomRedactionEventContent,
             topic::RoomTopicEventContent,
         },
         TimelineEventType,
@@ -182,7 +183,7 @@ enum AdminCommand {
 
 #[derive(Debug)]
 pub enum AdminRoomEvent {
-    ProcessMessage(String),
+    ProcessMessage(String, ruma::OwnedEventId),
     SendMessage(RoomMessageEventContent),
 }
 
@@ -221,7 +222,7 @@ impl Service {
                     Some(event) = receiver.recv() => {
                         let message_content = match event {
                             AdminRoomEvent::SendMessage(content) => content,
-                            AdminRoomEvent::ProcessMessage(room_message) => self.process_admin_message(room_message).await
+                            AdminRoomEvent::ProcessMessage(room_message, event_id) => self.process_admin_message(room_message, &event_id).await
                         };
 
                         let mutex_state = Arc::clone(
@@ -258,9 +259,12 @@ impl Service {
         }
     }
 
-    pub fn process_message(&self, room_message: String) {
+    pub fn process_message(&self, room_message: String, event_id: &EventId) {
         self.sender
-            .send(AdminRoomEvent::ProcessMessage(room_message))
+            .send(AdminRoomEvent::ProcessMessage(
+                room_message,
+                event_id.into(),
+            ))
             .unwrap();
     }
 
@@ -270,8 +274,57 @@ impl Service {
             .unwrap();
     }
 
+    /// Delete user message in the conduit admin room.
+    pub async fn delete_user_message(
+        &self,
+        event_id: &EventId,
+        reason: Option<impl Into<String>>,
+    ) -> Result<()> {
+        let conduit_user =
+            UserId::parse_with_server_name("conduit", services().globals.server_name())
+                .expect("@conduit:server_name is valid");
+        if let Some(room_id) = services().admin.get_admin_room()? {
+            let mutex_state = Arc::clone(
+                services()
+                    .globals
+                    .roomid_mutex_state
+                    .write()
+                    .await
+                    .entry(room_id.clone())
+                    .or_default(),
+            );
+            let state_lock = mutex_state.lock().await;
+
+            services()
+                .rooms
+                .timeline
+                .build_and_append_pdu(
+                    PduBuilder {
+                        event_type: TimelineEventType::RoomRedaction,
+                        content: to_raw_value(&RoomRedactionEventContent {
+                            redacts: Some(event_id.into()),
+                            reason: reason.map(Into::into),
+                        })
+                        .expect("event is valid, we just created it"),
+                        unsigned: None,
+                        state_key: None,
+                        redacts: Some(event_id.into()),
+                    },
+                    &conduit_user,
+                    &room_id,
+                    &state_lock,
+                )
+                .await?;
+        }
+        Ok(())
+    }
+
     // Parse and process a message from the admin room
-    async fn process_admin_message(&self, room_message: String) -> RoomMessageEventContent {
+    async fn process_admin_message(
+        &self,
+        room_message: String,
+        event_id: &EventId,
+    ) -> RoomMessageEventContent {
         let mut lines = room_message.lines().filter(|l| !l.trim().is_empty());
         let command_line = lines.next().expect("each string has at least one line");
         let body: Vec<_> = lines.collect();
@@ -287,7 +340,10 @@ impl Service {
             }
         };
 
-        match self.process_admin_command(admin_command, body).await {
+        match self
+            .process_admin_command(admin_command, body, event_id)
+            .await
+        {
             Ok(reply_message) => reply_message,
             Err(error) => {
                 let markdown_message = format!(
@@ -330,6 +386,7 @@ impl Service {
         &self,
         command: AdminCommand,
         body: Vec<&str>,
+        event_id: &EventId,
     ) -> Result<RoomMessageEventContent> {
         let reply_message_content = match command {
             AdminCommand::RegisterAppservice => {
@@ -591,6 +648,7 @@ impl Service {
                 }
             }
             AdminCommand::CreateUser { username, password } => {
+                let is_auto_generated_password = password.is_none();
                 let password =
                     password.unwrap_or_else(|| utils::random_string(AUTO_GEN_PASSWORD_LENGTH));
                 // Validate user id
@@ -645,6 +703,18 @@ impl Service {
                     .expect("to json value always works"),
                 )?;
 
+                // We'll delete the user message because it's contain a plain password
+                // and the admin room are not encrypted
+                if !is_auto_generated_password {
+                    services()
+                        .admin
+                        .delete_user_message(
+                            event_id,
+                            Some("Message contained a plaintext password"),
+                        )
+                        .await?;
+                }
+
                 // we dont add a device since we're not the user, just the creator
 
                 // Inhibit login does not work for guests

src/service/rooms/timeline/mod.rs

@@ -499,7 +499,7 @@ impl Service {
 
                     if let Some(admin_room) = services().admin.get_admin_room()? {
                         if to_conduit && !from_conduit && admin_room == pdu.room_id {
-                            services().admin.process_message(body);
+                            services().admin.process_message(body, &pdu.event_id);
                         }
                     }
                 }